EM 2040 Multibeam echo sounder

EM 2040
Multibeam echo sounder
True wide band high resolution
multibeam echo sounder

EM 2040
Key facts
The EM 2040 multibeam echo
sounder is the first system to bring
all the advanced features of deep
water multibeams to the near bottom
sounding environment. Important
deep water system features included
with the EM 2040 are:
• Dual swath per ping to allow a
doubling of survey speed
• FM chirp to achieve a much longer
range capability
• Complete roll, pitch and yaw
stabilization
• Nearfield focusing both on
transmit and receive
The EM 2040 is modular, allowing
the user to tailor the beamwidths to
the operational requirements, 0.5 by
1 and 1 by 1 degrees. The transmit
fan is divided into three sectors
pinging simultaneously at separate
frequencies. This ensures a very
strong and beneficial dampening
of multibounce interference which
on simpler systems often is seen at
beam angles from 60 degrees and
outwards. The EM 2040 has dual
swath capability, allowing a sufficient
sounding density alongtrack at a
reasonable vessel speed, for example
8 knots achieving 100% coverage
with a 0.5 degree transmit fan.
The operating bandwidth available
on the EM 2040 is unprecedented,
from 200 to 400 kHz, which is a
full octave, and this is achieved
with the standard transducers. The
operator can thus on the fly choose
the best operating frequency for
the application, 300 kHz for near
bottom, 200 kHz for deeper waters,
and 400 kHz for very high resolution
inspection.
The bandwidth of the EM 2040
transducers allows the system to
effectively operate with very short
pulse lengths, i.e. down to 25
microseconds. With 25 microseconds
pulse length the raw range resolution
(cτ/2) will be less than 20 mm.
The EM 2040 is well suited for
surveys meeting the IHO-S44 special
order.
The standard depth rating of the
EM 2040 subsea parts is 6000 m.
The system is thus fully prepared
for operation on subsea vehicles
such as AUVs or ROVs. All analog
electronics are contained in the
transducers, and communication to the
topside Processing Unit is on standard
Ethernet. For subsea vehicle use the
Processing Unit may be mounted in a
pressure vessel with an inner diameter
as small as 230 mm.
Components
The basic EM 2040 has four
units, a transmit transducer, a receive
transducer, a processing unit, and a
workstation. For completeness, data
input from a motion sensor and a
positioning system is required, as is
the sound speed profile of the water
column between the transducers
and the bottom. Sound speed at the
transducer is an optional input.
The EM 2040 is delivered with a
mounting plate with factory aligned
guidances. It is recommended that
the mounting plate is built into a steel
casing and protected by a baffle for
multipath reduction. Optionally, the
transducers may be delivered mounted
on a frame together with the motion
sensor and a sound speed sensor,
factory aligned for ease of mounting.
The EM 2040 is a modular system,
fully prepared for upgrading to cater
for more demanding applications. The
transmit transducer has an angular
coverage of 200º (±100º) as standard,
allowing a coverage of 5.5 times
water depth when matched with a
single receive transducer. Adding
a second receive transducer allows
surveying to the water surface or up to
10 times water depth on flat bottoms.
The transducers are separate units
with titanium housings.
The transducers are interfaced to
a processing unit via Ethernet, 100
Megabit/s to the transmit transducer
and Gigabit from the receive

EM 2040
transducer. The Processing Unit also
supplies power to the transducers.
Operator control, data quality
inspection and data storage is handled
by the hydrographic workstation
running the same SIS software as all
other Kongsberg multibeams.
Operational modes
The EM 2040 has a frequency
range of 200-400 kHz. Three
standard modes are available. 300
kHz is used for normal operation,
giving an optimum balance between
high resolution, depth capability
and tolerance of detrimental factors
such as water column sediments.
200 kHz is available for meeting
requirements to operate at the
standard hydrographic single beam
Advanced functions
• Frequency range: 200 to 400 kHz
frequency, but also to achieve the best
depth capability. 400 kHz is provided
for inspection work with the utmost
resolution.
The normally recommended
survey frequency is 300 kHz. At this
frequency the bandwidth used is more
than 75 kHz with three angular sectors
which are run at separate frequencies.
With dual swath six separate
frequencies are used. The minimum
pulselength is 35 microseconds. The
range resolution is then 26 mm. For
deep waters FM chirp is employed
with a bandwidth of 1.7 kHz. This
allows a swath width in the order of
550 m and a depth capability of about
350 m in cold ocean waters.
The 200 kHz frequency mode
has the same CW pulselengths as
the 300 kHz mode. The FM chirp
pulselength is extended compared
to the 300 kHz mode. Normally two
sectors are used per swath. At this
frequency the absorption in the water
is lower than at 300 kHz, resulting
in increased swath width and depth
capability. In cold ocean waters with
FM chirp a swath width of 700 m can
be expected, and approximately 500
m depth capability achieved.
The 400 kHz frequency mode is
intended for high resolution inspection
work. Very short transmit pulses and
wide receiver bandwidth is used. The
operator may choose between one and
three transmit sectors. With a single
RX transducer the coverage can be
up to 120º (±60º), and with dual RX
the coverage can be up to 180º (±90º).
The shortest pulse used is 25 µs. It is
also possible to run dual swath, but
not with the shortest pulse length.
• Dual swath capability, allowing a sufficient sounding density alongtrack
at a reasonable survey speed
• FM chirp allowing much longer range capability
• Complete roll, pitch and yaw stabilization
• Nearfield focusing on both transmit and receive
• Operates with very short pulse lengths, down to 25 microseconds
• The depth rating of the subsea parts is 6000 m
Transducer array (Rx/Tx)
Monitor
HydrographicWork Station (HWS)
Processing Unit (PU)

Technical specifications*
• Frequency range: 200 to 400 kHz
• Max ping rate: 50 Hz
• Swath coverage sector: Up to 140º
(±70º) (single RX) / 200 º (±100º)
(dual RX)
• Sounding patterns:
Equiangular, Equidistant and High
Density
• Roll stabilized beams: Yes, +/-15°
• Pitch stabilized beams: Yes, +/-10°
• Yaw stabilized beams: Yes, +/-10°
0.5 x 1 degrees ** Max depth Max coverage
Operating frequency Cold ocean Fresh water Cold ocean Fresh water
200 kHz 500 m 1070 m 740 m 1520 m
300 kHz 370 m 590 m 580 m 920 m
400 kHz 200 m 270 m 310 m 420 m
1 x 1 degrees ** Max depth Max coverage
Operating frequency Cold ocean Fresh water Cold ocean Fresh water
200 kHz 470 m 1000 m 700 m 1410 m
300 kHz 360 m 560 m 550 m 860 m
400 kHz 180 m 250 m 290 m 390 m
Pulse lengths 200 kHz 300 kHz 400 kHz
CW FM CW FM CW FM
Normal mode 70, 200 and 600 µs 12 ms 70, 200 and 600 µs 6 ms 50 and 100 µs N/A
Single sector mode 35, 70 and 150 µs 1.5 ms 35, 70 and 150 µs 1.5 ms 25 and 50 µs N/A
Max no. of soundings per ping (dual swath) 200 kHz 300 kHz 400 kHz
Single RX 1° RX 800 800 800
Dual RX 1° RX 1600 1600 1600
Physical dimensions (excluding connectors and mounting arrangements)
200 kHz 300 kHz 400 kHz Dimensions Weight
Tx 0.75° 0.5° 0.4° 727 x 150 x 142 mm (L x H x W) 45 kg
Tx 1.5° 1° 0.75° 407 x 150 x 142 mm (L x H x W) 24 kg
Rx 1.5° 1° 0.75° 407 x 136 x 142 mm (L x H x W) 23 kg
Processing Unit (4U 19” rack)*** 447 x 178 x 345 mm (W x H x D) 15 kg
Hydrographic Work Station (4U 19” rack) 427 x 178 x 480 mm (W x H x D) 20 kg
19” Monitor 483 x 444 x 68 mm (W x H x D) 12 kg
* Preliminary specifications. All options may initially not be available
** Beamwidths applicable to 300 kHz
*** More than one Processing Unit may be necessary
Kongsberg Maritime is engaged in continuous development of its products, and reserves the right to alter the
specifications without further notice.
332644 / Rev.F / March 2011
Kongsberg Maritime AS
Strandpromenaden 50
P.O.Box 111
N-3191 Horten,
Norway
Telephone: +47 33023800
Telefax: +47 33044753
www.kongsberg.com
subsea@kongsberg.com